This invention relates to a metal terminal and a connector for mounting on a board which connector employs such metal terminals.
The Unexamined Japanese Patent Application Publication No. Hei 8-203591 discloses a board-mounted-type connector 100 shown in FIGS. 18 to 21. This board-mounted-type connector 100 comprises a housing 110, metal terminals 120A and 120B, and a retainer 130.
The large-size metal terminal 120A includes a fitting portion 121A for receiving a mating male metal terminal (not shown), and a board-mounting portion 123A. The board-mounting portion 123A has a resilient flexing portion 122A of a V-shape, and this portion is resiliently deformable so as to prevent an excessive stress from developing in the other portion of the metal terminal 120A. The board-mounting portion 123A is adapted to be inserted into a mounting hole H formed through a board P. The small-size metal terminal 120B also includes a fitting portion 121B, a resilient flexing portion 122B and a board-mounting portion 123B which achieve similar functions as described above for the large-size metal terminal.
Large-size cavities 111A for respectively receiving the large-size metal terminals 120A are formed in opposite (right and left in FIG. 18) end portions of the housing 110, and a plurality of small-size cavities 111B for respectively receiving the small-size metal terminals 120B are also formed in the housing, and are arranged between the opposite-end large-size cavities 111A. Fitting holes 113A and 113B for respectively passing the mating male metal terminals therethrough are formed in an upper surface (FIG. 18) (hereinafter referred to as "fitting surface 112"), and communicate respectively with the cavities 111A and 111B, the fitting holes 113A and 113B being open to the outer surface (i.e., the fitting surface). The cavities 111A and 111B are open to a mounting surface 114 facing away from the fitting surface 112, and the retainer 130 is mounted on this mounting surface 114. Engagement portions 118 each having an engagement hole 118A are formed on and project from side marginal portions of the mounting surface 114 of the housing 110. The engagement holes 118A are engageable respectively with engagement projections 139A formed on the retainer 130, and the housing 110 and the retainer 130 are held in an interconnected condition by this engagement. Bosses 119 are formed on the opposite ends of the housing 110, respectively, and these bosses 119 are fitted respectively in boss holes 141, formed in the retainer 130, when the housing 110 is connected to the retainer 130. A screw hole 119A is formed through each boss 119, and can be aligned with a corresponding screw hole (not shown) in the board P, and a screw (not shown) can pass through this screw hole 119A so as to fixedly secure the board-mounted-type connector 100 to the board P.
The retainer 130 conforms in configuration to the mounting surface 114 of the housing 110, and has receiving chambers 133A and 133B which can be aligned with the cavities 111A and 111B, respectively. When the retainer 130 and the housing 110 are connected together, the resilient flexing portions 122A and 122B are received respectively in the receiving chambers 133A and 133B in such a manner that each resilient flexing portion 122A, 122B is sufficiently spaced from the peripheral surface of the receiving chamber 133A, 133B that it can be resiliently deformed. The receiving chambers 133A and 133B have positioning holes 136A and 136B, respectively, which are open to that surface of the retainer 130 to be abutted against the board P. The engagement projections 139A, engageable respectively in the engagement holes 118A in the housing 110, are formed on the side surfaces of the retainer 130. Plate-like portions 140 extend respectively from the opposite ends of the retainer 130, and have the boss holes 141, respectively, into which the bosses 119 on the housing 110 can be fitted, respectively.
For assembling the board-mounted-type connector 100, the housing 110 is disposed with its mounting surface 114 directed upwardly, and the metal terminals 120A and 120B are disposed with their fitting portions 121A and 121B directed downwardly, and then are caused to drop respectively into the cavities 111A and 111B by their own weight.
After the metal terminals 120A and 120B are thus inserted respectively into the cavities 111A and 111B, the retainer 130 is connected to the housing 110. When the engagement projections 139A are engaged respectively in the engagement holes 118A of the engagement portions 118, the retainer 130 is locked to the housing 110 against disengagement. At this time, the bosses 119 on the housing 110 are fitted respectively into the boss holes 141 in the retainer 130.
In this assembled condition of the board-mounted-type connector 100, the board-mounting portions 123A and 123B, projecting from the retainer 130, pass respectively through the positioning holes 136A and 136B, and therefore are properly positioned as shown in FIG. 20.
For mounting the board-mounted-type connector 100 on the board P, the board-mounted-type connector 100 is disposed with the board-mounting portions 123A and 123B opposed to the board P, and the screw holes 119A are aligned respectively with the screw holes (not shown) in the board P, and the board-mounted-type connector 100 is fixedly secured to the board P by screws (not shown).
After the board-mounting portions 123A and 123B are thus fitted respectively in the mounting holes H, the board-mounting portions 123A and 123B are fixedly secured to the board P by soldering Q (see FIG. 21).
In the condition shown in FIG. 21, a mating connector (not shown), having the mating male metal terminals (not shown) mounted therein, is fitted relative to the board-mounted-type connector 100 from the upper side. When the two connectors are fitted together, the distance between the mutually-connected portions of each mating pair of metal terminals and the board P is equal to the distance (hereinafter referred to as "distance R") between the fitting surface 112 and the upper surface of the board P. This distance R is generally equal to the overall length of the metal terminals 120A and 120B.
When the two connectors, after fitted together, are vibrated independently of each other (for example, if these connectors are mounted on an automobile, such a situation can be encountered depending on the type of vibration of the automobile), a force, acting on those portions of the two metal terminals in contact with each other, is received by the soldered portion Q. A moment, acting on the soldered portion Q, is proportional to the distance R, and in the conventional construction, this distance R is inevitably equal to the overall length of the metal terminals 120A and 120B, and as a result the large moment acts on the soldered portion Q.
In the conventional construction, since the distance between the board P and the mutually-connected portions of the two metal terminals is equal to-the distance R, and therefore a large moment can inevitably act on the soldered portion Q, depending on the type of vibration.
The board-mounted-type connector 100 is mounted on the board P, and then is fitted relative to the mating connector, and in this condition, when the two connectors are energized, heat is often generated at part of the board P with the lapse of time. When part of the board P generates heat, the board P thermally expands according to the distribution of the heat. As a result, a force, tending to bring the board-mounting portions 123A and 123B out of alignment with the respective mounting holes H, acts on the soldered portions Q.